Publicação
Design and fabrication of a intervertebral disk with a hydroxyapatite bone interface and a reinforced hydrogel annulus/nucleus
| Resumo: | Neck pain can be severely debilitating, affecting in one way or another thousands of people across the world. This pain can be caused by a large amount of factors, chief among them intervertebral disk related. This structure is present in between our vertebrae and is responsible for load bearing, while maintaining the entire vertebral column mobile. Several methods are available to help with the abatement of neck pain, including physical therapy, anti-inflammatory and analgesic medication in the mildest of cases. With harsher conditions, surgeries might be done to remove bone growths that press against the spinal chord and heat treatments can be applied to disk’s tissue to alleviate accumulated tensions. When the disk is considered irreparable and the patient qualifies for it, a replacement surgery is done. This surgery can take two forms: one where the vertebrae are fused after the removal of the disk and another where the disk is replaced by a mechanical device designed to mimic its properties. Even with these options, there are several problems and limitations associated with the disk replacement. Considering the aforementioned information, the goal of this thesis is to contribute to the landscape by developing an artificial intervertebral disk, that replicates the native one’s properties. Starting with a detailed state of the art review, covering the cervical disk anatomy, pathologies and repair/replacement techniques, followed by an analysis of the bio-materials available to achieve the project’s goal. The second phase of the project entailed the design and manufacture of the implant, starting with the hydroxyapatite endplate fabrication and hydrogel cross-linking optimization for the PVA/PAAm and PHEMA/PMMA materials. After that, several samples were made, including artificial disks with the endplates and a mono or bi-gel core. These samples were then mechanically tested under compression and shear, as a block and individually for each component. Beyond this characterization, the PVA/PAAm hydrogels were also characterized via Micro-CT, XRD, FTIR and SEM, the latter also being utilized to analyze the endplates. This study was conducted to explore the polymeric combinations mentioned earlier, which were selected based on previously reported studies. Although it was feasible to produce discs that had good adhesion between the endplates and the hydrogel, the resulting mechanical properties were significantly inferior to those of the original disc. This work aims to enhance the understanding of the properties associated with these materials, with the intention of facilitating future research in this field. |
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| Autores principais: | Tavares, João Pedro Oliveira |
| Assunto: | Biomechanics Intervertebral disk Cervical disk Hydrogel Degenerative disk disease Hydroxyapatite |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | português |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Neck pain can be severely debilitating, affecting in one way or another thousands of people across the world. This pain can be caused by a large amount of factors, chief among them intervertebral disk related. This structure is present in between our vertebrae and is responsible for load bearing, while maintaining the entire vertebral column mobile. Several methods are available to help with the abatement of neck pain, including physical therapy, anti-inflammatory and analgesic medication in the mildest of cases. With harsher conditions, surgeries might be done to remove bone growths that press against the spinal chord and heat treatments can be applied to disk’s tissue to alleviate accumulated tensions. When the disk is considered irreparable and the patient qualifies for it, a replacement surgery is done. This surgery can take two forms: one where the vertebrae are fused after the removal of the disk and another where the disk is replaced by a mechanical device designed to mimic its properties. Even with these options, there are several problems and limitations associated with the disk replacement. Considering the aforementioned information, the goal of this thesis is to contribute to the landscape by developing an artificial intervertebral disk, that replicates the native one’s properties. Starting with a detailed state of the art review, covering the cervical disk anatomy, pathologies and repair/replacement techniques, followed by an analysis of the bio-materials available to achieve the project’s goal. The second phase of the project entailed the design and manufacture of the implant, starting with the hydroxyapatite endplate fabrication and hydrogel cross-linking optimization for the PVA/PAAm and PHEMA/PMMA materials. After that, several samples were made, including artificial disks with the endplates and a mono or bi-gel core. These samples were then mechanically tested under compression and shear, as a block and individually for each component. Beyond this characterization, the PVA/PAAm hydrogels were also characterized via Micro-CT, XRD, FTIR and SEM, the latter also being utilized to analyze the endplates. This study was conducted to explore the polymeric combinations mentioned earlier, which were selected based on previously reported studies. Although it was feasible to produce discs that had good adhesion between the endplates and the hydrogel, the resulting mechanical properties were significantly inferior to those of the original disc. This work aims to enhance the understanding of the properties associated with these materials, with the intention of facilitating future research in this field. |
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